1. Field of the Invention
This invention relates to a pedal-controlled movable bottom frame, particularly to one pivotally assembled on the lower portions of four stationary support legs of a worktable, able to be controlled by pedaling to take the place of the four support legs to support the worktable and make it slidable on the ground.
2. Description of the Prior Art
Generally, most medium-sized or small-sized processing machines, such as planers, sanders and the like, are respectively provided with four stationary support legs to maintain the height and support the weight of a worktable. When such a worktable needs to be transferred from one place to another, it has to be moved by manpower or by special carriers, taking too much time and labor in transfer of the worktable. In view of the above-mentioned defect, the worktable has its four legs respectively provided at the lower end with a caster with a brake able to control the worktable to be stopped or moved slidably. Nevertheless, such casters are likely to be damaged after used for a period of time and have no excellent effect in braking, likely to cause sway to the worktable to influence the precision and quality of processing when the machine operates. Additionally, each caster is independently assembled on each leg of the worktable; therefore each caster has to be braked or released respectively, resulting in much inconvenience in use.
In the U.S. Pat. Nos. 5,976,173, 5,957,649 and 6,311,992, a worktable has its legs provided at the lower end with a support frame with casters, which can be shrunk inward and positioned at an upper position of the legs of the worktable and also can be controlled to stand on the ground to lift up the worktable and move it slidably by means of the casters.
However, the foresaid support frame is generally made of two separate frames combined together so it is complicated in structure and inconvenient in assembly, increasing producing and assembling cost.